1. Field of the Invention:
This invention relates to torches. More particularly, it relates to cutting torches having a plurality of tubes therewithin. In a particular aspect, it relates to an improvement in cutting torches, particularly the large machine cutting torches in which it is vital that the cutting tip maintain the same relative position with respect to the work piece, since there is no human welder to compensate for changes in this relationship.
2. Description of the Prior Art:
The advent of welding solved many problems that had plagued manufacturers earlier. The use of torches, such as cutting torches, welding torches, heating torches and the like also helped the repairman perform a variety of repairs on the site instead of having to return an article to the factory to be repaired. With the ever increasing costs of labor, there is a move toward increased automation. One of the problems; namely, bowing of a cutting torch; that has plagued the welder causes an intolerable variance when automated cutting or welding, as by machine cutting torches, is employed. Specifically, in the past, the tendency for manually employed torches to bow because of differential heating between the cutting oxygen tube and the mixing tube in the torch could be compensated for by the welder who watched the flame impinge upon the desired area and could control the tip to compensate and cut the desired portion. With machine welding, however, there is no manual compensation so it is vital that the cutting torch tip maintain the same relative relationship to the work piece as initially employed if the uniform arcs, circles and the like that are made by the machine are to be correctly translated into the cuts made by the torch tip.
A variety of attempts have been made in the prior art to correctly compensate for the variance. These attempts have included forceably holding the torch tip with respect to the work piece and allowing the top portion of the torch to bow; and making the tubes within the torch of different materials having different degrees of thermal expansion so as to try to compensate for the differential cooling. The first solution has resulted in some instability in the torch affixing and operation. The second has not compensated for the different degrees of thermal expansion because of the different modes in which the torch will be operated, including initial heating mode, followed by the high flow rate of cutting oxygen with its greater cooling of the cutting tube assembly.
Thus, it can be seen that the prior art has not provided a totally satisfactory solution to the problem of the tendency of the cutting torch to bow due to differential expansion of tubes therewithin; and, consequently, alter the relationship of the tip relative to the work piece. Expressed otherwise, there have been no satisfactory solutions to the cocking of the torch tip with respect to a work piece during cutting. Yet, it is vital that this problem be solved, particularly with respect to machine cutting torches.